6 files changed, 109 insertions, 60 deletions

diff --git a/lib/lsan/CMakeLists.txt b/lib/lsan/CMakeLists.txt
index 2ea765de1bc7..37f794e2e11b 100644
--- a/lib/lsan/CMakeLists.txt
+++ b/lib/lsan/CMakeLists.txt
@@ -18,20 +18,13 @@ set(LSAN_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 add_custom_target(lsan)
 
-if(APPLE)
-  foreach(os ${SANITIZER_COMMON_SUPPORTED_DARWIN_OS})
-    add_compiler_rt_darwin_object_library(RTLSanCommon ${os}
-      ARCH ${LSAN_COMMON_SUPPORTED_ARCH}
-      SOURCES ${LSAN_COMMON_SOURCES}
-      CFLAGS ${LSAN_CFLAGS})
-  endforeach()
-else()
-  foreach(arch ${LSAN_COMMON_SUPPORTED_ARCH})
-    add_compiler_rt_object_library(RTLSanCommon ${arch}
-      SOURCES ${LSAN_COMMON_SOURCES}
-      CFLAGS ${LSAN_CFLAGS})
-  endforeach()
+add_compiler_rt_object_libraries(RTLSanCommon
+    OS ${SANITIZER_COMMON_SUPPORTED_OS}
+    ARCHS ${LSAN_COMMON_SUPPORTED_ARCH}
+    SOURCES ${LSAN_COMMON_SOURCES}
+    CFLAGS ${LSAN_CFLAGS})
 
+if(COMPILER_RT_HAS_LSAN)
   foreach(arch ${LSAN_SUPPORTED_ARCH})
     add_compiler_rt_runtime(clang_rt.lsan-${arch} ${arch} STATIC
       SOURCES ${LSAN_SOURCES}
diff --git a/lib/lsan/lsan_common.cc b/lib/lsan/lsan_common.cc
index b9e2a1104326..0ffba505cc70 100644
--- a/lib/lsan/lsan_common.cc
+++ b/lib/lsan/lsan_common.cc
@@ -21,7 +21,6 @@
 #include "sanitizer_common/sanitizer_procmaps.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
-#include "sanitizer_common/sanitizer_stoptheworld.h"
 #include "sanitizer_common/sanitizer_suppressions.h"
 #include "sanitizer_common/sanitizer_report_decorator.h"
 
@@ -127,13 +126,14 @@ static inline bool CanBeAHeapPointer(uptr p) {
 
 // Scans the memory range, looking for byte patterns that point into allocator
 // chunks. Marks those chunks with |tag| and adds them to |frontier|.
-// There are two usage modes for this function: finding reachable or ignored
-// chunks (|tag| = kReachable or kIgnored) and finding indirectly leaked chunks
+// There are two usage modes for this function: finding reachable chunks
+// (|tag| = kReachable) and finding indirectly leaked chunks
 // (|tag| = kIndirectlyLeaked). In the second case, there's no flood fill,
 // so |frontier| = 0.
 void ScanRangeForPointers(uptr begin, uptr end,
                           Frontier *frontier,
                           const char *region_type, ChunkTag tag) {
+  CHECK(tag == kReachable || tag == kIndirectlyLeaked);
   const uptr alignment = flags()->pointer_alignment();
   LOG_POINTERS("Scanning %s range %p-%p.\n", region_type, begin, end);
   uptr pp = begin;
@@ -147,9 +147,7 @@ void ScanRangeForPointers(uptr begin, uptr end,
     // Pointers to self don't count. This matters when tag == kIndirectlyLeaked.
     if (chunk == begin) continue;
     LsanMetadata m(chunk);
-    // Reachable beats ignored beats leaked.
-    if (m.tag() == kReachable) continue;
-    if (m.tag() == kIgnored && tag != kReachable) continue;
+    if (m.tag() == kReachable || m.tag() == kIgnored) continue;
 
     // Do this check relatively late so we can log only the interesting cases.
     if (!flags()->use_poisoned && WordIsPoisoned(pp)) {
@@ -288,7 +286,7 @@ static void MarkIndirectlyLeakedCb(uptr chunk, void *arg) {
   LsanMetadata m(chunk);
   if (m.allocated() && m.tag() != kReachable) {
     ScanRangeForPointers(chunk, chunk + m.requested_size(),
-                         /* frontier */ 0, "HEAP", kIndirectlyLeaked);
+                         /* frontier */ nullptr, "HEAP", kIndirectlyLeaked);
   }
 }
 
@@ -298,8 +296,11 @@ static void CollectIgnoredCb(uptr chunk, void *arg) {
   CHECK(arg);
   chunk = GetUserBegin(chunk);
   LsanMetadata m(chunk);
-  if (m.allocated() && m.tag() == kIgnored)
+  if (m.allocated() && m.tag() == kIgnored) {
+    LOG_POINTERS("Ignored: chunk %p-%p of size %zu.\n",
+                 chunk, chunk + m.requested_size(), m.requested_size());
     reinterpret_cast<Frontier *>(arg)->push_back(chunk);
+  }
 }
 
 // Sets the appropriate tag on each chunk.
@@ -307,26 +308,33 @@ static void ClassifyAllChunks(SuspendedThreadsList const &suspended_threads) {
   // Holds the flood fill frontier.
   Frontier frontier(1);
 
+  ForEachChunk(CollectIgnoredCb, &frontier);
   ProcessGlobalRegions(&frontier);
   ProcessThreads(suspended_threads, &frontier);
   ProcessRootRegions(&frontier);
   FloodFillTag(&frontier, kReachable);
+
   // The check here is relatively expensive, so we do this in a separate flood
   // fill. That way we can skip the check for chunks that are reachable
   // otherwise.
   LOG_POINTERS("Processing platform-specific allocations.\n");
+  CHECK_EQ(0, frontier.size());
   ProcessPlatformSpecificAllocations(&frontier);
   FloodFillTag(&frontier, kReachable);
 
-  LOG_POINTERS("Scanning ignored chunks.\n");
-  CHECK_EQ(0, frontier.size());
-  ForEachChunk(CollectIgnoredCb, &frontier);
-  FloodFillTag(&frontier, kIgnored);
-
   // Iterate over leaked chunks and mark those that are reachable from other
   // leaked chunks.
   LOG_POINTERS("Scanning leaked chunks.\n");
-  ForEachChunk(MarkIndirectlyLeakedCb, 0 /* arg */);
+  ForEachChunk(MarkIndirectlyLeakedCb, nullptr);
+}
+
+// ForEachChunk callback. Resets the tags to pre-leak-check state.
+static void ResetTagsCb(uptr chunk, void *arg) {
+  (void)arg;
+  chunk = GetUserBegin(chunk);
+  LsanMetadata m(chunk);
+  if (m.allocated() && m.tag() != kIgnored)
+    m.set_tag(kDirectlyLeaked);
 }
 
 static void PrintStackTraceById(u32 stack_trace_id) {
@@ -372,35 +380,33 @@ static void PrintMatchedSuppressions() {
   Printf("%s\n\n", line);
 }
 
-struct DoLeakCheckParam {
+struct CheckForLeaksParam {
   bool success;
   LeakReport leak_report;
 };
 
-static void DoLeakCheckCallback(const SuspendedThreadsList &suspended_threads,
-                                void *arg) {
-  DoLeakCheckParam *param = reinterpret_cast<DoLeakCheckParam *>(arg);
+static void CheckForLeaksCallback(const SuspendedThreadsList &suspended_threads,
+                                  void *arg) {
+  CheckForLeaksParam *param = reinterpret_cast<CheckForLeaksParam *>(arg);
   CHECK(param);
   CHECK(!param->success);
   ClassifyAllChunks(suspended_threads);
   ForEachChunk(CollectLeaksCb, &param->leak_report);
+  // Clean up for subsequent leak checks. This assumes we did not overwrite any
+  // kIgnored tags.
+  ForEachChunk(ResetTagsCb, nullptr);
   param->success = true;
 }
 
-void DoLeakCheck() {
-  EnsureMainThreadIDIsCorrect();
-  BlockingMutexLock l(&global_mutex);
-  static bool already_done;
-  if (already_done) return;
-  already_done = true;
+static bool CheckForLeaks() {
   if (&__lsan_is_turned_off && __lsan_is_turned_off())
-      return;
-
-  DoLeakCheckParam param;
+      return false;
+  EnsureMainThreadIDIsCorrect();
+  CheckForLeaksParam param;
   param.success = false;
   LockThreadRegistry();
   LockAllocator();
-  StopTheWorld(DoLeakCheckCallback, &param);
+  DoStopTheWorld(CheckForLeaksCallback, &param);
   UnlockAllocator();
   UnlockThreadRegistry();
 
@@ -424,25 +430,42 @@ void DoLeakCheck() {
     PrintMatchedSuppressions();
   if (unsuppressed_count > 0) {
     param.leak_report.PrintSummary();
-    if (flags()->exitcode) {
-      if (common_flags()->coverage)
-        __sanitizer_cov_dump();
-      internal__exit(flags()->exitcode);
-    }
+    return true;
   }
+  return false;
+}
+
+void DoLeakCheck() {
+  BlockingMutexLock l(&global_mutex);
+  static bool already_done;
+  if (already_done) return;
+  already_done = true;
+  bool have_leaks = CheckForLeaks();
+  if (!have_leaks) {
+    return;
+  }
+  if (flags()->exitcode) {
+    if (common_flags()->coverage)
+      __sanitizer_cov_dump();
+    internal__exit(flags()->exitcode);
+  }
+}
+
+static int DoRecoverableLeakCheck() {
+  BlockingMutexLock l(&global_mutex);
+  bool have_leaks = CheckForLeaks();
+  return have_leaks ? 1 : 0;
 }
 
 static Suppression *GetSuppressionForAddr(uptr addr) {
   Suppression *s = nullptr;
 
   // Suppress by module name.
-  const char *module_name;
-  uptr module_offset;
   SuppressionContext *suppressions = GetSuppressionContext();
-  if (Symbolizer::GetOrInit()->GetModuleNameAndOffsetForPC(addr, &module_name,
-                                                           &module_offset) &&
-      suppressions->Match(module_name, kSuppressionLeak, &s))
-    return s;
+  if (const char *module_name =
+          Symbolizer::GetOrInit()->GetModuleNameForPc(addr))
+    if (suppressions->Match(module_name, kSuppressionLeak, &s))
+      return s;
 
   // Suppress by file or function name.
   SymbolizedStack *frames = Symbolizer::GetOrInit()->SymbolizePC(addr);
@@ -679,6 +702,15 @@ void __lsan_do_leak_check() {
 #endif  // CAN_SANITIZE_LEAKS
 }
 
+SANITIZER_INTERFACE_ATTRIBUTE
+int __lsan_do_recoverable_leak_check() {
+#if CAN_SANITIZE_LEAKS
+  if (common_flags()->detect_leaks)
+    return __lsan::DoRecoverableLeakCheck();
+#endif  // CAN_SANITIZE_LEAKS
+  return 0;
+}
+
 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 int __lsan_is_turned_off() {
diff --git a/lib/lsan/lsan_common.h b/lib/lsan/lsan_common.h
index 2c3a12ab6bd8..4f9d24fb3ab9 100644
--- a/lib/lsan/lsan_common.h
+++ b/lib/lsan/lsan_common.h
@@ -19,6 +19,7 @@
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_internal_defs.h"
 #include "sanitizer_common/sanitizer_platform.h"
+#include "sanitizer_common/sanitizer_stoptheworld.h"
 #include "sanitizer_common/sanitizer_symbolizer.h"
 
 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__mips64)) \
@@ -99,6 +100,8 @@ typedef InternalMmapVector<uptr> Frontier;
 void InitializePlatformSpecificModules();
 void ProcessGlobalRegions(Frontier *frontier);
 void ProcessPlatformSpecificAllocations(Frontier *frontier);
+// Run stoptheworld while holding any platform-specific locks.
+void DoStopTheWorld(StopTheWorldCallback callback, void* argument);
 
 void ScanRangeForPointers(uptr begin, uptr end,
                           Frontier *frontier,
diff --git a/lib/lsan/lsan_common_linux.cc b/lib/lsan/lsan_common_linux.cc
index ba51868c76e8..2955343e1f0b 100644
--- a/lib/lsan/lsan_common_linux.cc
+++ b/lib/lsan/lsan_common_linux.cc
@@ -85,10 +85,6 @@ static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,
 // Scans global variables for heap pointers.
 void ProcessGlobalRegions(Frontier *frontier) {
   if (!flags()->use_globals) return;
-  // FIXME: dl_iterate_phdr acquires a linker lock, so we run a risk of
-  // deadlocking by running this under StopTheWorld. However, the lock is
-  // reentrant, so we should be able to fix this by acquiring the lock before
-  // suspending threads.
   dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);
 }
 
@@ -114,7 +110,7 @@ static void ProcessPlatformSpecificAllocationsCb(uptr chunk, void *arg) {
       reinterpret_cast<ProcessPlatformAllocParam *>(arg);
   chunk = GetUserBegin(chunk);
   LsanMetadata m(chunk);
-  if (m.allocated() && m.tag() != kReachable) {
+  if (m.allocated() && m.tag() != kReachable && m.tag() != kIgnored) {
     u32 stack_id = m.stack_trace_id();
     uptr caller_pc = 0;
     if (stack_id > 0)
@@ -153,5 +149,30 @@ void ProcessPlatformSpecificAllocations(Frontier *frontier) {
   ForEachChunk(ProcessPlatformSpecificAllocationsCb, &arg);
 }
 
+struct DoStopTheWorldParam {
+  StopTheWorldCallback callback;
+  void *argument;
+};
+
+static int DoStopTheWorldCallback(struct dl_phdr_info *info, size_t size,
+                                  void *data) {
+  DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data);
+  StopTheWorld(param->callback, param->argument);
+  return 1;
+}
+
+// LSan calls dl_iterate_phdr() from the tracer task. This may deadlock: if one
+// of the threads is frozen while holding the libdl lock, the tracer will hang
+// in dl_iterate_phdr() forever.
+// Luckily, (a) the lock is reentrant and (b) libc can't distinguish between the
+// tracer task and the thread that spawned it. Thus, if we run the tracer task
+// while holding the libdl lock in the parent thread, we can safely reenter it
+// in the tracer. The solution is to run stoptheworld from a dl_iterate_phdr()
+// callback in the parent thread.
+void DoStopTheWorld(StopTheWorldCallback callback, void *argument) {
+  DoStopTheWorldParam param = {callback, argument};
+  dl_iterate_phdr(DoStopTheWorldCallback, &param);
+}
+
 }  // namespace __lsan
 #endif  // CAN_SANITIZE_LEAKS && SANITIZER_LINUX
diff --git a/lib/lsan/lsan_interceptors.cc b/lib/lsan/lsan_interceptors.cc
index ba2519dcb25d..61a92154d95e 100644
--- a/lib/lsan/lsan_interceptors.cc
+++ b/lib/lsan/lsan_interceptors.cc
@@ -208,7 +208,7 @@ extern "C" void *__lsan_thread_start_func(void *arg) {
   // Wait until the last iteration to maximize the chance that we are the last
   // destructor to run.
   if (pthread_setspecific(g_thread_finalize_key,
-                          (void*)kPthreadDestructorIterations)) {
+                          (void*)GetPthreadDestructorIterations())) {
     Report("LeakSanitizer: failed to set thread key.\n");
     Die();
   }
diff --git a/lib/lsan/lsan_thread.h b/lib/lsan/lsan_thread.h
index 4641b32ed6e6..99e2c1d5e64b 100644
--- a/lib/lsan/lsan_thread.h
+++ b/lib/lsan/lsan_thread.h
@@ -22,8 +22,8 @@ namespace __lsan {
 class ThreadContext : public ThreadContextBase {
  public:
   explicit ThreadContext(int tid);
-  void OnStarted(void *arg);
-  void OnFinished();
+  void OnStarted(void *arg) override;
+  void OnFinished() override;
   uptr stack_begin() { return stack_begin_; }
   uptr stack_end() { return stack_end_; }
   uptr tls_begin() { return tls_begin_; }